2019 ASHS Annual Conference

Plant resistance/susceptibility to environmental stresses varies among potato varieties. In addition, Ca appears to play a role in membrane stability which appears to be related to internal heat necrosis (IHN), one of the main problems of the chipping cultivar ‘Atlantic’ in Virginia. This study investigated differences in membrane stability and the role of Ca fertilization between two potato varieties that differ in their resistance/susceptibility to (IHN), a disorder that results in the browning of the flesh while still in the field. In addition, the relationship with Ca fertilization was evaluated. Potatoes in this study showed very little or no IHN suggesting that stress conditions were not sufficient to induce IHN. For membrane stability, potato tissue was exposed to increasing temperatures and Electrical conductivity (ion leakage) was greater (P=0.02d) in the susceptible cultivar ‘Atlantic’ over ‘Sebec’ (resistant cultivar) by 38% at 45 °C. There were no differences at any other temperature treatment. This suggests that cell membrane in ‘Sebec’ potato is more stable under heat stress than ‘Atlantic’ and suggest a possible factor in the susceptibility/resistance to IHN. Tissue Ca content was not different among cultivars and treatments, so the association of Ca and membrane stability could not be corroborated. Polyphenol oxidase activity in flesh tissue was higher in ‘Sebec’ than ‘Atlantic’ (P=0.0146). In contrast, there was no differences in peroxidase activity (P=0.1618) and phenolic content (P =0.1065) between the varieties and Ca treated and untreated tubers. In conclusion, results support previous studies that suggested that cell membrane stability is likely a factor in IHN susceptibility/resistance.